This invention relates to toothbrushes. More particularly the invention is concerned with an apparatus facilitating the use of ultrasonic energy to assist an otherwise manual toothbrush in loosening and removing soft plaque from the teeth of the user on a substantially daily basis. A specific concern of the invention is an apparatus that carries the bristle clusters, which is readily replaceable as wear of the bristles occur. Another concern is the therapeutic treatment of oral tissue, and specifically treatment and prevention of mouth sores.